A New Zealand man who bought an MP3 player from a thrift shop in Oklahoma found it held 60 U.S. military files, including names and telephone numbers for American soldiers, a media report said Tuesday.
TV One News said the 60 files contained personal details of U.S. soldiers, including some who had served in Afghanistan and Iraq.
A New Zealand security expert said the information should not be in the public domain, but that it did not appear likely to affect U.S. national security.
The U.S. Embassy declined to comment on the incident.
Similar breaches occurred in Afghanistan in 2006, when U.S. investigators reportedly bought back stolen flash drives that contained sensitive military data from shops outside a main U.S. base in the Afghan city of Bagram.
Chris Ogle, 29, from the northern New Zealand city of Whangarei, said he bought the music player at a thrift shop in Oklahoma, and that he found the files when he linked the $18 device to his computer, TV One News reported.
The report did not say exactly where and when the device was purchased, and Ogle could not be reached by The Associated Press for comment Tuesday.
The private information about troops included U.S. Social Security numbers and even which female troops were pregnant, TV One reported.
Details of equipment deployed to bases in Afghanistan and a mission briefing were also found on some files, the report said, displaying names like "Bagram," a main U.S. base in Afghanistan, from the files on screen.
A TV One News reporter called some of the phone numbers listed in the files and found that some of them were still active.
Some of the files included a warning that the release of its contents is "prohibited by federal law."
Most of the files are dated 2005 so are unlikely to compromise U.S. national security, said Peter Cozens, director of Victoria University of Wellington's Strategic Studies Department.
"This is just slack administrative procedures which are indeed a cause of embarrassment," Cozens said. "It's the sort of thing which ought not really to be in the public domain."
Ogle told TV One News he would hand the files to U.S. officials if asked.
"The more I look at it, the more I see and the less I think I should be" looking, Ogle said.
Janine Burns, a spokeswoman for the U.S. Embassy in the capital, Wellington, told the AP, "We have nothing to add at this time."
She had no response to Ogle's offer to hand over the electronic files.
It's not the first time such data files have surfaced in public.
In 2006, shopkeepers outside the Bagram base said they were selling flash drives with U.S. military information that had been stolen by some of the 2,000 Afghans employed as cleaners, office staff and laborers at Bagram.
Included on some memory drives seen by AP at the time were the Social Security numbers of hundreds of soldiers, including four generals, and lists of troops who had completed nuclear, chemical and biological warfare training.
The Los Angeles Times also reported that some drives had classified military secrets, including maps, charts and intelligence reports that appeared to detail how Taliban and Al Qaeda leaders had been using southwestern Pakistan as a planning and training base for attacks in Afghanistan.